Volume Booster and airpod Booster can enhance the volume of sound not only in headphones and earphones, but also it can make speaker louder. But for a better effect and better sounding we recommend you to use headphones and airpods.
Volume Booster – Equalizer FX comes with bass boost and equalizer settings to up the game of listening to music. You can change the bass level from two different categories easily with . It also has an integrated music player where you can play your songs and modify them immediately within the app. Simple interface makes the Volume Booster – Equalizer FX app a considerable choice over the others

Disclaimer:
Playing audio at a high volume for a long time may damage your hearing.